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- Description
- Specifications
A 1RU router from the Cisco 4000 Series Integrated Services Routers, sized for larger branch offices. It has 4 onboard 10/100/1000 WAN/LAN ports, which Cisco lists as 4 SFP-capable and 4 RJ-45, plus 3 network interface module (NIM) slots and 1 onboard ISC slot. Unlike the ISR 4331, it has no service-module (SM) slot.
Aggregate throughput is 500 Mbps by default and 1 Gbps with the performance licence, and the boost licence allows over 4 Gbps of CEF-only forwarding. The control and services plane has 4 GB of DRAM by default, expandable to 16 GB, and the data plane has a fixed 2 GB. Flash is 8 GB by default, expandable to 32 GB.
It takes internal AC, DC or PoE power supplies and supports a redundant supply. With PoE supplies, the platform delivers up to 500 W to endpoints with PoE redundancy, or 1000 W in PoE boost mode without redundancy. DC input is 48 to 60 V. The chassis measures 1.73 x 17.25 x 19.97 in, deeper than the 4331.
Lifecycle: Cisco announced end of sale on November 7, 2022. The last order date was November 7, 2023, software maintenance releases ended on August 31, 2025, and the last date of support is November 30, 2028. Cisco lists two replacements: the Catalyst C8300-1N1S-4T2X and C8300-1N1S-6T.
When replacing one, record the installed NIMs, power supplies and throughput licence, since all three vary between units.
More from this family: Cisco Router.
Related parts: ISR4331/K9.
| ISR4431/K9 Specs | |
| Part number | ISR4431/K9 (ISR4431-K9, ISR4431K9) |
| Series | Cisco 4000 Series ISR |
| Form factor | 1RU (1.73 x 17.25 x 19.97 in) |
| Onboard ports | 4 x GE (4 SFP-capable, 4 RJ-45) |
| Expansion | 3 NIM, 1 ISC, no SM |
| Throughput | 500 Mbps default; 1 Gbps (performance); over 4 Gbps CEF (boost) |
| DRAM | 4 GB default, 16 GB max (control/services); 2 GB data plane |
| Flash | 8 GB default, 32 GB max |
| Power | Internal AC, DC or PoE; redundant option |
| PoE to endpoints | 500 W redundant, 1000 W boost |
| End of sale / last support | November 7, 2023 / November 30, 2028 |
| Replacement | C8300-1N1S-4T2X or C8300-1N1S-6T |